slashsound wrote:You dont need to know anything about tube construction to know that physics is the same regardless of what device you are talking about. If say for example material x has a capacitance, resistance, impedance, density, heat capacity, and so and and so forth ....then there are many many ways to achieve the same or practiacally the same properties from engineered materials. This is fact, dont dispute it. Everything is reproducable if you have enough information... variations in missing elements ( such as those that contain toxins no longer allowed by law) can be mimiced through modern materials. Have an electrical engineer dispute this... they wont. Your opinions are still appreciated.
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I'm afraid your experience in this subject isn't going to sway me...since you have none.
Ha! I hate to tell you this, but I've posed questions to engineers about sound/speaker failures/etc. several times on the TGP forum. Of course their theories/physics/etc. couldn't explain them. In theory (or physics) there's no reason for certain things to happen, but they do. It comes down to experience. They knew theoretical practices that "should" result in something. However, actual practice/use/failures didn't match their predictions/theories/assumptions.
It's the same thing with old tubes, certain reactions occur based on the materials used, and how they interact with each other under certain conditions. Change one piece of that interaction and the result changes slightly. You can't argue the sound/impact of a tube's construction when it's built one way 50-60 years ago, then try to "approximate" or "mimic" it with modern materials without being able to reverse engineer the critical design features/materials/etc.
The problem with your physics, practically speaking, is that they can't reproduce that interaction. So your "facts" do not relate, nor do they have any relevance or bearing on the materials, gases, and sonic textures imparted inside of a vacuum tube, unless they account for all of the related parts, gases, and results of those old parts.
So, in fact, I can dispute this, because you can't reproduce many of the materials that went into an old vacuum tube due to EPA/environmental restrictions, and those properties can't be "replicated" practically speaking, or hearing...yet.
You've got a whole shitload of research to do on this, and frankly, until you've got a few million bucks behind you to get it done, this isn't something you should be posting on, IMO.
As someone who has done some research on replicating certain tones, I can tell you this much...you might be able to get damned close if you are diligent, and have enough pristine/excellent samples to use as tone targets for tubes. But then are you willing to buy enough known good tubes, then can sacrifice them for examination (something I did for speakers) by someone qualified to replicate them? I'm willing to bet you haven't got those resources.
As I said, many have tried before you, and failed. But by all means, if you really want to pursue this, do what you have to do! I'll outline it for you, which is what I did to replicate the old pre rola Greenback tone.
1) Go on a mission, get fanatical. Learn enough about what you're replicating to have a serious understanding of your final product.
2) Be prepared to buy hundreds of old Mullard EL34 XF2's and 12AX7's (and whatever other tubes you're thinking of reproducing).
3) Have a discerning enough ear to know what's truly exceptional, and what just "passes tests" as new. That's a difference that will be super critical to the success of your quest. You'll likely need help which you'll have to pay for.
4) Find the funding to buy 4-500 old tubes, plus the proper amps to figure out which ones are the best. That should set you back around $100k right there. (I spent $77k doing this over 6 years ago on speakers, by the way.)
5) After you've found the holy grail tubes to replicate, find enough qualified tube people that agree with your ears findings to lend their talents to the task. Trust me, this will be really tough, and expensive. You're treading on ground others have gone down with no success.
6) After finding your holy grail tubes, find some tubes you can/will autopsy (sacrifice) that are built within the same tolerances, ridiculously close manufacturing time frame (typically within weeks,or two months), and materials as your holy grails that can be used as donor tubes for someone to measure and figure out all of the materials after taking them apart. Date codes on tubes will likely be something you need to learn.
7) Then pay someone with the "physics" to replicate it to the nth degree. I'm figuring this will be a huge dollar figure.
Let me know when you'll be offering up your Mullard clones, I've got some beauties that I've stashed (no you can't have them for your research!) for comparison. I even have the amps to test them in (no you can't have the amps, either!). If you pull it off, I'll buy your tubes, assuming they don't cost what real NOS glass costs (Mullard XF2 NOS EL34's are something around $350-500 per pair, I believe).
Get started, let me/us/the world of guitar players who relish these tubes know when you've got it done.
Once you find out just how daunting this task is, I won't be surprised if you don't take it on, can't get the funding, or just plain give up due to the complexities involved. And then, sir, your physics will let you down in a big way. I think until you come up with said tube, you should probably quit posting about this as something you have a handle on, because it's clear to me you are not learned enough in this subject yet.
But here's to your efforts. Good luck!
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